


Instigation

by Uturuncu



Category: Kingdom Hearts
Genre: Canon Compliant, Cutscene Expansion, Emotional Sadism, Emotions as Sustenance, Empath, Gen, Heartless - Freeform, Hollow Bastion (Kingdom Hearts), Mindfuck, Nightmare Fuel, POV Ansem Seeker of Darkness, POV Third Person Limited, Realm of Darkness (Kingdom Hearts), Sharing a Body, body theft, locked in syndrome
Language: English
Status: Completed
Published: 2017-09-27
Updated: 2017-09-27
Packaged: 2019-01-05 22:39:14
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,700
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12198816
Author URL: https://archiveofourown.org/users/Uturuncu/pseuds/Uturuncu
Summary: Riku loses his battle with Sora. In that moment, he knows it is time for ten years of plotting to come to fruition.





	Instigation

**Author's Note:**

> Sister fic to [The Fall](https://archiveofourown.org/works/12191310)

            He was watching when the Keyblade responded to Riku's call, when it rejected Sora and moved to the stronger wielder. It was satisfying, so very satisfying, to see his project succeed as he was supposed to from the start. How little Terra had known that passing the Mark on was merely damning the boy he had seen such potential in.

            He was still watching when the Keyblade reversed its decision and returned to the younger boy's hand. Riku fought well, of course, the boy had been trained well, had already had a level of inherent knowledge in swordplay from practicing against the other children as he grew up. There was a reason he had a reputation as the best on his island.

            The fight was, however, three against one, and Riku wielded only a regular blade versus the power of a Key of Light. Even with all the Darkness he dared call to himself, it wasn't enough to trump that of Sora and his friends. It was disappointing, but also expected the moment that Riku's heart faltered and the Key left him.

            And still he watched, following Riku through the castle as he fled the fight before he could be properly defeated. The turmoil in the boy's Heart was delicious, and he knew now it was finally time. As the Islander rushed into the chapel, he broke his silence in a desperate cry to himself. "Why? It was mine!" He immediately took his opportunity.

            "Know this," he spoke, though his voice emitted from nowhere, no body to produce the sound. It was omnipresent, nondirectional, and he was only able to speak due to the level of Darkness in this area of the castle, so very close to the Door to Darkness. The flash of fear from the pale boy as he stumbled to a halt when spoken to brought yet more delight. "The Heart that is strong and true will win the Keyblade." As he spoke, he found he was able to manifest in this area.

            Not fully, no. He hadn't been able to manifest a physical form outside of the depths of the Realm of Darkness itself since he had unbound his Heart from his body a decade ago. The form he took was the same as always in the physical world, an empty robe in a vaguely humanoid shape. Riku's response was primarily confusion, wariness, and then following a crushing feeling of defeat. Good. He was vulnerable now, and that vulnerability was the ticket he needed to move forward with his plans.

            "What? You're saying my Heart's weaker than his?" came the response to his question. The hesitance in his Heart spoke that while the unbound being before him should make his final play, he did have to play it with care. This was the culmination of years of careful work and observation and one wrong step could destroy all he sought to achieve.

            As such, his voice rang out once more with both confirmation, but also a solution in one. One he was sure that the defeated Keybearer would bite on. "For that instant, it was." His target outright deflated, shoulders drooping, head bowing low. "However, you can become stronger. You showed no fear in stepping through the Door to Darkness. It held no terror for you." The confirmation that his weakness was temporary and something he could resolve brought a flash of hope that told Ansem in an instant he'd won.

            "Plunge deeper into the Darkness, and your Heart will grow even stronger," he finished, and it actually took effort for him to keep his voice even now, as he began to slowly approach the islander. Keeping his victorious satisfaction out of his tone, keeping it steady, was a point of pride for him. Generally he didn't bother to master the emotions he felt all too strongly as an unbound Heart with none of the temperance afforded to a complete being.

            Riku's response, the flash of fear and dissent in his Heart immediately put the unbound being on edge. Perhaps his victory was not yet in his grasp. It seemed that damnable faerie had trained the boy well in how to safely command the Darkness without losing himself. Such a strange relationship the two had. She treated him with a callous disregard on the surface, like a pawn in her games. At the same time, though, Ansem's observations of the two's interactions showed a different side that she kept hidden away. She almost saw the islander as a surrogate son, and her teachings were fueled by a legitimate desire to protect him from a fall.

            When the pale boy deflated once more, though, he began to feel his assurance of victory return. "What should I do?" It was so very clear that his defeat at Sora's hands was gnawing away from him, and even that he had opted to flee rather than continue the fight like a coward was tearing him apart as well. Perfect. It was perfect. This was exactly where he needed the islander to be.

            "It's really quite simple. Open yourself to the Darkness. That is all." He became aware that the Darkness was responding to his own satisfaction even without his call. Yet more of it was rippling into the room, flooding towards Riku as an extension of himself. The boy's confusion was palpable at this new sensation of Darkness that held purpose rather than indifference. That, in itself, was amusing. Once more, keeping his voice even was an effort, "Let your Heart, your being, become Darkness itself."

            Oh the conflict that tore through Riku at those final words. He could feel the boy's fear, he could feel how he knew better than to heed that instruction. And he could feel the moment the balance shifted and the trepidation was forced away for acceptance. His approach quickened as he tasted his now sealed victory. But the flow of Darkness into Riku stopped, giving Ansem pause. As green flame began to flow around the boy, he cursed the faerie once more. So her protection extended as far as outright shielding her charge from the Darkness, as if knowing he was susceptible to the fall and ensuring he would not.

            The sudden burst of anger out of the islander, then, was almost a surprise; he'd thought the stoppering of the flow of Darkness would bring the boy pause, not cause him to double down on his efforts. That anger allowed the Darkness to war against the barrier, and Ansem helped it along by forcing more of it towards him. It was a further surprise that it was so easy for Riku to burn away the shield; he expected more of the faerie's power than that. Or, perhaps, he had underestimated the pale boy before him. Certainly that was a higher point of satisfaction, proving that he had been right in choosing Riku as his project, and playing the long game that lead to this point.

            He was so close now, his ethereal form very near to the boy, and so much of the Darkness flowing into him. It wasn't just a physical closeness, but a closeness to what he desired so strong it was as if he could taste it in his nonexistent mouth. At this point the Darkness was forcing itself into Riku's body, overflowing his attempted control. They were inches apart. And then the islander, the poor, foolish boy realized the gravity of his mistake. It was too late.

Riku's attempt to stop the flow of Darkness was much like trying to stop a wave by putting up one's hand. The resistance was outright negligible. His attempt to back away, to flee, was equally fruitless as Ansem snatched a hold of the Darkness within him to freeze him in place. As the pale boy's body got closer and closer, he did not slow, his own ethereal form phasing into the physical body before him. _Yes, **yes!**_

            Once he had entered Riku's body, he felt the screaming terror that flooded through him almost as if it was his own. For a bare moment, he withstood that but he soon made a decision for it to cease. With a mere thought, the boy's Darkened Heart was outright ejected from his body, banishing him away to the Realm of Darkness to allow Ansem the chance to revel in his new form.

His hands roamed over the body that was now his, grasping and touching at it, feeling something that might even be called 'joy' at owning a body of flesh and blood for the first time since he rejected his own so very long ago. He was warm, he could feel a pulse, the sensation of breath flowing into his lungs, his sight different than the odd, Darkness-based senses he had before. This was real, this was _alive_ , and now he could affect the worlds in a physical manner. A booming laugh of victory broke from him, then, and he only felt more pleasure at the way it echoed around and vibrated through his chest and lungs.

            It was a bit odd, as well, because that laugh wasn't entirely his. Riku's throat was still Riku's, and despite him being in control he had Riku's voice. He was aware of his own flowing in an ethereal manner around him, as well, but the boy's voice was just as defined. And, of course, he was a child again which was equally unnerving. Smaller, weaker than his original form, he squeezed at the toned but not particularly defined muscles of the boy's body. It was going to be difficult to adjust to the loss of physical strength and his old height.

            A step forward was taken, and to his surprise he stumbled. It was a further surprise as his knees and the heels of his palms struck the ground, a flash of unfamiliar pain rushing up from the impact. He gave a low hiss from the sensation and felt a flow of frustration through him as he stared at the ground from a kneeling position. He, the Seeker of Darkness, had tripped on air?! This body was not his own, did not move like his own. Still, somehow, he was used to a physical form he hadn't worn in ten years.

            Shorter, slimmer, his sense of balance was off, his ability to walk hindered by legs the wrong length. Even attempting to push himself up to standing was an embarrassment, as he swung up with the force it would have taken to move his old mass. And then promptly ended up seated on a sore rump on the marble once more. Anger seethed through him at how pathetic he must look, and the only saving grace was that no one was around to see it.

            The sensation of his face flushing with blood and heat was almost distressing as this new body reacted to his mix of anger and a bit of shame. For several long minutes he sat on the floor of the chapel, attempting to figure out how he would master this body quickly enough to make use of it. There was little time, after all, with the Princesses gathered and the final Heart in the castle working its way up to its body. Finally, it came to him.

            He was going to need Riku after all. Ejecting him from his body left Ansem with no reference point for how, precisely, to use it. Retrieving the boy's Heart would allow him to pinpoint precisely how to use this body and give him the memories of its use he needed to actually use the form. It would also allow him to tap into very necessary combat experience in this particular form.

            Aqua eyes were closed as Ansem projected himself into the Realm of Darkness, taking care to keep a foothold on the body and not leave it abandoned and empty for something else to steal from him. Even with a physical form it was remarkably easy to project his true body into the Darkness as he had many times in the past. And there before him was Riku, standing upon the shore with dark waters lapping at his shoes.

            It was a surprise when Riku instantly recognized his presence and whirled on him, though he mastered that away to a smug smirk at the sight of the now bodiless islander. "Who are you!? _What_ are you!?" came the boy's shout. He could tell that Riku was wrong footed by the unusual nature of the Realm of Darkness. But he was perfectly at home. The attempt to arm himself and the resultant distress at failing was yet more fuel to Ansem's amusement, drawing him to shake his head slowly and outright chuckle at the weakness of the boy before him.

            "Perhaps you should have asked those questions before you heeded my instruction to give yourself to the Darkness. A mistake, on your part, but quite the boon on mine, Riku." And yet he had been almost certain, all along, that this was how things would end when he finally achieved his goal. He had always attempted to keep contingencies but as the years flowed on he became more and more laser focused on Riku. If this hadn't played out exactly as planned, he would have been in a very bad spot, would have needed to start over. Somehow.

            "Just answer me!" came the snap from the islander, drawing a yet wider smirk across Ansem's features. He gave a pause, measuring his response carefully. It also functioned as a way to draw more of Riku's frustration, giving him yet more of that negative energy to feed upon. Finally, as that frustration mounted, he opted to respond in that slow, even voice.

            "Are you sure you want the answer to those questions? Perhaps you would be better off not knowing. It might break your pitiful little mind." There, he paused once more, to give a bit more weight to an unanswered question. "Or for you to know how long I've been with you." He knew Riku was struggling with some form of familiarity with him, and the fact that the pale boy couldn't place it was yet more amusing. As was his confirmation that this was not a first meeting and the resultant confusion from the boy. Once more, though, Riku snapped to anger. At this point it seemed his default state, after Ansem had caught him at such an emotional weak point.

            "Of course I want the answers! That's why I _asked_ ," broke out louder than before in a near yell. Was Riku actually shaking with his frustration? It certainly seemed it, though perhaps that was merely the vibration of his Heart responding to the height of the emotions flooding through him. Now, then, seemed the perfect time to introduce himself.

            "My name... Is Ansem. The Seeker of Darkness," he said, lowly, eyes flashing and arms opening wide to indicate himself. For a moment, he expected some recognition of his name, of him being the King of Hollow Bastion. That never came, though; apparently the faerie had kept a few details about the castle she resided in to herself. It didn't really matter, though, he supposed. He didn't immediately answer the second question, allowing the islander to begin growing frustrated again, waiting until the exact moment his mouth opened to shout once more before actually speaking.

            "As to what I am? You would not even begin to comprehend it. It would be simplest to say I am a Heartless, but it is such a bare, simple designation that it's almost incorrect. An unbound Heart, free to travel the Darkness at will, to command it, and with the power to command any creature of Darkness with a mere thought. Heartless, yes, but those who have fallen, as well." The clack of Riku's teeth as his mouth snapped shut when he spoke was amusing, tingeing his words with the width of his smirk. As soon as he was done speaking, he began walking towards the pale boy, taking full advantage of his confusion.

            When Riku suddenly realized that he was being approached, it was again too late for him to do anything. Though, of course, in the Realm of Darkness it wasn't possible to get far enough away from Ansem to be safe. This was his home, the locus of his power, and no interloper here could even hope to best him. Still, though, the islander attempted to jump away from him with a loud yell of surprise. It was the matter of mere thought to raise the dark sand behind his heels and solidify it, sending him toppling into the water behind him.

            Before Riku even had the chance to attempt to get up, Ansem had phased through the Darkness. No longer was he standing feet away, but over the boy with a hand planted either side of his head, his knees at his sides, and his weight on Riku's legs to pin him in place. The fact that they were touching brought a wonderful flare of horror from the islander beneath him.

            He had never been this close to Riku, not truly, not manifest in physical form in the Realm of Darkness like this. It was quite enjoyable to be here, to feel him, to see those aqua eyes so close to him open wide and with pupils dilated. The boy was _terrified_ , and that feeling sent a pounding through his body that he couldn't easily name. "Witness, _boy_ , the extent of my power," boomed from him, one hand coming up right over Riku's heart in an open claw, immediately beginning to sink it into his chest.

            It was inhuman, but not difficult, for Ansem to control exactly how solid his body was in places of such strong Darkness. His fingers slipped into Riku's chest like it was mere air, not getting caught or strung up on the ribs, lungs, or any other internal structures. They also did no damage as they passed through, just left a chill of Darkness in their wake as they broke apart filaments of Heart in their journey. When his still-corporeal palm struck Riku's sternum, the fingers clenched around the core of the boy's Heart, grasping it tightly.

            His face moved closer, then, his nose nearly touching Riku's, his head tilted in a way that their lips nearly brushed together, as well. He didn't require breath, so nothing actually puffed out of his mouth to create sound as he nearly hissed, "Allow me to demonstrate," with a manic intensity. So very eager, so very ready. The hand embedded in Riku's chest lifted, the grip on his Heart anchoring him like he actually had a physical grip, That grip dragged Riku's form up by the strands and tendrils of his Heart, run through his body in a manner similar to his natural veins and arteries.

            It was truly beautiful the way Riku's face had twisted up in agony from being dragged around by a part of him that should never be touched. Could never be touched by all but a bare handful of creatures. His eyes were wet with tears and the sound that was breaking from his mouth unbidden was the most perfect, choking moan of pain Ansem had ever had the delight of hearing. Their bodies did not touch as Ansem allowed his corporeality to fade so that their Hearts could touch, and as they connected he felt the boy go limp in his grip, before fading away.

            He allowed his form, now containing Riku's Heart in a cage of Darkness, to rubber band back to Hollow Bastion and back into the pale boy's body. The new Heart within him was warm and it was almost a pleasant feeling to be aware of him, imprisoned within. Even though Riku was not 'awake', so to speak, was still in a form of stasis from the shock of his Heart being consumed, Ansem was able to sift through his knowledge, through his memories. And then he stood.

            This time, there was no issue with balance, this time he didn't fall. He stood as easily as if this body had been his own for all of time. And that thought drew another flood of pleasure through him. He virtually reveled in the ability to walk towards the secret door within the chapel, to open it with a brush of his hand, passing between the Princesses of Heart in their cocoons.

            Maleficent was standing before the Door and he approached her. As he climbed the stairs he could feel a groggy consciousness returning to his mind. Riku was coming out of his shock, which drew an unbidden grin to his face. Stepping up beside her, he spoke almost idly, "So, I see the path has emerged at last." Again his voice was Riku's, but it overlapped with his own voice in that duotone. Oddly, the faerie either didn't notice, or didn't care that her charge had changed. Ansem couldn't dwell on that, though, not with the stimulation flooding his body of Riku's emotions and thoughts upon realizing he was a prisoner in his own body.

            They were so _raw_ , as if they were a part of him and yet not all at once. He was able to draw power from the emotion, but it left a residual impact on him, as well. At some level he could virtually read Riku's thoughts, so close were their Hearts entwined now. His next words were projected directly into the pale boy's thoughts, "You see? I command those fallen to Darkness, Riku. And you? Have fallen. You are nothing more than my puppet, now, my vessel." His amusement and satisfaction tore through Riku in a way similar to a verbal laugh, rising and falling with his pleasure at the situation.

            "Do enjoy the show as I end all that is dear to you and plunge the worlds into Darkness by your hand." As all the distress, terror, and self-loathing peaked within the entrapped islander, Ansem could outright feel the scream that tried, and failed, to escape his stolen body. And inside, that laughter became stronger from the possessor. He had won.

**Author's Note:**

> Welcome to my second offering for one of my favorite pairings of this fandom. It's still not smut, but hey. Last night I felt like writing the other POV of this fic, taking it from Ansem's side of things. This one ended up slightly more shippy, in the sense that it highlights Ansem's freaky-ass obsession with Riku, but doesn't really dip into anything sexual. Hold on to your butts, it's only going to go downhill into horror, kink, and trigger warnings from here.
> 
> By the way, go read this. Finally got inspired to start writing these two because of this. It's really good. [Dark Bound](https://archiveofourown.org/works/5996014/)


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